https://www.bleepingcomputer.com/news/microsoft/windows-11-kb5009566-update-released-with-security-fixes/ > Microsoft has released the Windows 11 KB5009566 cumulative update with security updates, performance improvements, and fixes for known bugs. > KB5009566 is a mandatory cumulative update as it contains the January 2022 Patch Tuesday security updates for vulnerabilities discovered in previous months.